The instant invention relates to apparatus for inserting sheet materials into envelopes, and more particularly to such apparatus capable of accommodating a variety of thicknesses of such materials.
Envelope stuffing machines, such as those shown in U.S. Pat. Nos. 4,169,341 and 4,337,609, both assigned to the assignee of the instant application, generally include: a conventional structure for delivering an envelope, with its address panel oriented upwardly and its flap opened, to a registration gate at an enclosure inserting station; conventional structure for timely opening the delivered envelope, including a plurality of fingers known in the art as stripper fingers, which are insertable into the throat of the envelope for opening the same; and conventional structure for inserting an enclosure into the opened envelope. Typically, the envelope opening structure includes a plate which acts as a ledge upon which the flap of the envelope is located when it is delivered to the inserting station. Moreover, one or more rigid finger members, known in the art as depressor fingers, are fixedly attached to the framework of the inserter apparatus and disposed in overhanging relationship with respect to the envelope's address panel, for depressing the body of the envelope downwardly against the resistance afforded by the envelope flap ledge to thereby partially open the throat of the envelope to facilitate insertion of the stripper fingers into the envelope.
Operators of the conventional inserters have experienced difficulties with them due to the aforesaid fixed depressor fingers tending to prevent delivery of the envelope to the registration gate. As a result, many operators have been bending the depressor fingers away from the path of travel of the envelope to ensure delivery to the registration gate, as a result of which the force exerted on the envelope by the depressor fingers is reduced and the envelope is insufficiently depressed to permit entry of the stripper fingers into the envelope for opening the same. Accordingly, misfeeds resulting from improper envelope registration and failure to open the envelopes have been found to be directly attributable to the provision of the fixed depressor fingers. The aforesaid U.S. Pat. No. 4,337,609 taught a partial solution to the problems generated by fixed depressor fingers by providing movable depressor fingers which normally hold the depressor fingers out of the path of travel of the envelope and for moving the depressor fingers into engagement with the envelope when a connective solenoid is enabled.
However, problems continued to persist using the movable depressor fingers. Accordingly, in U.S. Pat. No. 4,852,334 issued Aug. 1, 1989, the assignee of the instant invention provided an envelope opening apparatus which employs only a pair of orbital stripper claws and does not require the use of any depressor fingers, fixed or movable, and the substantial amount of apparatus associated therewith.
The aforesaid '334 patented inserting apparatus, unfortunately, suffers from a shortcoming inherent in virtually all inserters, i.e. an inability to reliably and consistently insert a variety of thickness of enclosures into envelopes. Therefore, the instant invention provides apparatus which assures that regardless of the thickness of a collation of enclosures, that the collation can be reliably and consistently inserted into the waiting envelopes.